In the case of systems to generate electrical energy, for instance wind power systems or solar power systems, current converter modules are used, which convert the generated direct voltage or alternating voltage to a voltage that has the frequency required by the grid connection point. Depending upon the application case, these types of converters can have a power transfer of several kW to several MW. Located inside the current converter module are fast-switching power semiconductors, for example bipolar transistors with insulated-gate bipolar transistor (IGBT for short). The heat that develops based on conversion losses is dissipated at one or more heat sinks. This heat must be dissipated by a corresponding cooling device so that the power semiconductor is not destroyed due to overheating.
The heat dissipated at the heat sinks is preferably conveyed directly to a heat exchanger, through which a cooling liquid flows. For example, a water/ethanol mixture or a water/glycol mixture is used as a cooling liquid to protect against corrosion or frost.
The cooling liquid is supplied in a cooling circuit, in turn, to an air cooler and correspondingly cooled there, before being led back, in turn, via a pump to the heat exchanger of the power semiconductor.
A problem with such a cooling circuit can be a condition where the temperature on the heat exchanger of a power semiconductor drops as an exception below the temperature of the ambient air. This case can occur, for example, when the current converter module is switched off during the execution of maintenance work. The result of this is a formation of condensation on the heat exchanger, which can cause damage to or even destroy electronic components.
Therefore, the problem addressed by the invention is preventing the formation of condensation in a cooling device for a current converter module.
This problem is solved by the features of present invention.
Additional embodiments of the present invention are disclosed.